1. Fields of the Invention
The present invention relates generally to an apparatus and method of lubricating dental handpieces and, more particularly, to a dispenser which delivers an accurately metered amount of dental handpiece lubricant to the turbine rotor and bearings of the handpiece prior to sterilization.
2. Discussion of Background and Prior Art
Heretofore three methods have been used to dispense lubricants into a dental handpiece prior to sterilization as follows:
1 In a method by Brown in U.S. Pat. No. 5,520,882 (xe2x80x9cthe Brown ""882 patentxe2x80x9d) there is described and claimed a dental handpiece lubricant that includes about 90% by volume of a liquid hydrocarbon and about 10% by volume of a lubricant enhancer and corrosion inhibitor, such as, NNL-690, which forms a eutectic film over the rotor bearings during the subsequent sterilizing step and extends handpiece life and is sold by Steri-Lube International, Ltd under the brand name Steri-Lube(trademark).
The Brown ""882 patent is hereby incorporated herein by reference. The Brown ""882 patent describes a method in which a small packet 10 containing a pre-measured amount of Steri-Lube(trademark) lubricant is squeezed to empty the packet contents 11 into the air intake hole 12 of the handpiece 13 while holding the handpiece upside down as seen in FIGS. 1, 2 of the present application. While the method described in the Brown ""882 patent delivers an accurate dose of the lubricant to the aft handpiece rotor assembly, the process is time consuming and clumsy, and the amount of lubricant that actually reaches the turbine rotor assembly varies from use to use depending on who performs the step and how it is performed.
2 Another prior method is performed by inverting a drop bottle containing the lubricant and squeezing the lubricant out through a needle attached to the bottle outlet opening and placing the drops into the air intake opening of the handpiece. This procedure does not deliver an accurate dose to the rotor assembly.
3 The third method is performed by dispensing the lubricant from a pressurized canister with a nozzle tip into the handpiece air intake opening and expelling the excess lubricant. This procedure not only does not deliver an accurate metered dose of the lubricant to the rotor assembly, but also, as described in greater detail below, reduces the ability of a lubricant enhancer and corrosion inhibitor lubricant, such as, Steri-Lube lubricant, to form its eutectic film over the handpiece rotor bearings during the subsequent autoclave step.
Accordingly, it is an object of the present invention to quickly (i.e., less than 1 second), simply (i.e., just push a button), accurately (i.e., +/xe2x88x9210% stroke-to-stroke, +/xe2x88x922 microliters with linear actuator), and efficiently (i.e., virtually all of the lubricant goes to and remains at the rotor assembly) dispense a predetermined dose (i.e., xe2x85x9-xc2xd ccs) of a dental handpiece lubricant onto the moving parts of a dental handpiece.
The prior Assistina(trademark) Model 301 Plus system made by WandH Dentalwerk Burmoos, A-5111 Burmoos, Austria, and distributed in the United States by A-DEC International, Inc., 2601 Crestview Drive, Newberg Oreg. 97132, automatically cleans, lubricates, and purges a dental handpiece prior to sterilization. In operation the spay air and spray water channels of the dental handpiece are connected via an adaptor to a 65 psi to 140 psi compressed air supply line which is apparently stepped down to an unspecified operating pressure level by an in line regulator. (It is noted that a typical air handpiece operates at 30-35 psi.) The connected handpiece is then placed in a cigar-shaped holder which is then placed into an operating chamber in the unit and a lid is closed to cover the chamber. Pressing and holding the start button for 2 seconds initiates a timed 35 second cycle which, in pre-programmed, non-selectable, automatic sequence, first flushes cleaning fluid through the spray air and spray water channels, then injects a metered dose of ordinary service oil to lubricate the internal working parts of the handpiece, and then finally purges the handpiece by applying compressed air to blow the spray air and spray water channels free of the cleaning solution and the internal moving parts free of any excess oil. It is estimated that the minimum pressure needed to overcome inertia and spin the turbine rotor sufficiently fast to throw off the excess oil is not less than about 25 psi. The unit comes with two universal adaptors for maintaining more than one handpiece type.
There are many problems with this unit including: (1) it is very expensive, retailing for about $1,820.00 at the time of filing the present application; (2) it is very slow (35 seconds) and complex (3 operations in every cycle); (4) the individual operations are not independently selectable by the user, but rather come bundled as an automatic preprogrammed sequence; (5) it does not disclose or suggest dispensing a dental handpiece lubricant, such as the Steri-Lube(trademark) lubricant, that includes about 90% by volume of a liquid hydrocarbon and about 10% by volume of a lubricant enhancer and corrosion inhibitor, such as, NNL-690, which forms a eutectic film over the rotor bearings during the subsequent sterilizing step; (6) the mandatory cleaning step destroys much of the remaining eutectic film built up over the rotor bearings as a result of any previous use prior to sterilization of a lubricant enhancer and corrosion inhibitor type lubricant, such as, the Steri-Lube(trademark) lubricant; and, (7) the mandatory purging step blows out the excess lubricant using an unspecified, but inherently high, air pressure (estimated at 25 psi minimum to 35 psi maximum) prior to the sterilizing step to prevent over-oiling, thereby removing a significant portion, if not virtually all, of the excess lubricant, which step would deprive a lubricant enhancer and corrosion inhibitor type dental handpiece lubricant, such as Steri-Lube(trademark), from having a sufficient dose of the lubricant to form an optimal, long lasting eutectic film under the heat of the subsequent autoclave even if such a lubricant enhancer and corrosion inhibitor type lubricant, such as, the Steri-Lube(trademark) lubricant, were to be used therein.
Accordingly, it an object of the present invention to dispense the measured amount of the dental lubricant to the rotor turbine assembly during each application without first cleaning or purging prior to sterilization.
It is a further object of the present invention to dispense a lubricant enhancer and corrosion inhibitor type lubricant, such as, the Steri-Lube(trademark) dental handpiece lubricant, into the air intake line of a dental handpiece by metering the measured amount of said lubricant under such circumstances (2.6 psi while holding the handpiece upside down and using a long needle nosed tip) as to assure that a sufficient supply of said lubricant to enable the formation of an effective eutectic film during the subsequent autoclave cycle reaches, but does not go beyond, the rotor assembly during each application prior to sterilization.
Set forth below is a brief summary of the invention which achieves the foregoing and other objects and provides the foregoing and hereafter stated benefits and advantages in accordance with the structure, function and results of the present invention as embodied and broadly described herein. Applicant""s invention includes independently both the apparatuses and the methods described herein which achieve the objects and benefits of the present invention. Both formats of the invention are described below, and it is applicant""s intention to claim both formats even though from time to time below for purposes of clarity and brevity applicant will use either one or the other format to describe various aspects and features of the invention.
One aspect of the invention is a dental handpiece lubricant dispenser which includes a housing, a pump supported on the housing having inlet and outlet ports, the inlet port coupled to a lubricant supply and the outlet port coupled to a tube having an outlet opening, for delivering a predetermined amount of the lubricant during an activated cycle of the pump, an actuator supported on the housing adapted to be coupled to a power supply, and when cycled causing the pump to deliver a predetermined amount of the lubricant through the outlet port and tube to the outlet opening, and a switch which is independently selectable for cycling the actuator to activate only the active cycle of the pump.
A further feature of this aspect of the invention include he actuator is the actuator is a spring biased solenoid and the pump is a piston-diaphragm type.
A further feature of this aspect of the invention include he actuator is the actuator is a timer circuit with relay and the pump is a motor driven type.
Further features of this aspect of the invention are the active cycle of the pump is activated without also activating a cleaning cycle or a purging cycle, the active cycle of the pump is about one second in duration, the predetermined amount of lubricant which is delivered is in the range of about xe2x85x9 to xc2xd cc, the lubricant comprises about 90% by volume of a liquid hydrocarbon and about 10% by volume of a lubricant enhancer and corrosion inhibitor, the liquid hydrocarbon is a pharmaceutical grade mineral oil and the lubricant enhancer and corrosion inhibitor is NNL-690, the about 90% by volume of a liquid hydrocarbon includes the range of 80% to 97% by volume and the about 10% by volume of a lubricant enhancer and corrosion inhibitor includes the range of 3% to 20% by volume, the cycle has a duration which is adjustable and controls the predetermined amount of lubricant delivered by the pump, the predetermined amount of the lubricant is delivered during an activated cycle of the pump at a pressure of about 2.6 psi into the air intake hole of the handpiece while holding the handpiece upside down so as to assure that a sufficient supply of the lubricant to enable the formation of an effective eutectic film during a subsequent sterilization step reaches and remains in a rotor assembly of the handpiece, and, an adaptor may be secured on the outlet of the tube having an elongated nozzle for dispensing the lubricant well down into the air intake hole of the handpiece to assure delivery of the maximum amount of the predetermined amount of lubricant as near as possible to the rotor assembly of the handpiece.
The dispenser of the present application has no cleaning function or purpose whatsoever. The dispenser of the present application is used solely for dispensing lubricating oil prior to sterilization, or, as described in greater detail below, for post sterilization lubrication if a separate dispensing mechanism is provided for that function. A totally independently selectable purge function for use solely after sterilization or after post-sterilization lubrication may be provided as an additional option to clear excess oil in the handpiece, as described in greater detail below.
The advantages of the invention are:
1 Fast dispensing of the dose amount.
2 Simple dispensing of the dose amount, just push a button.
3 Accurate dispensing of a measured dose amount (i.e., xe2x85x9-xc2xd ccs).
4 Inexpensive dispensing operations, the estimated retail price being ⅙th of prior art units which perform a similar function.
5 Enabled use of lubricant enhancer and corrosion inhibitor type lubricants, such as, Steri-Lube(trademark) lubricant, for pre-sterilization lubrication with promised vastly improved effectiveness in extending the life of the handpieces.
6 Metered dispensing of said Steri-Lube(trademark) type lubricant under such circumstances (2.6 psi while holding the handpiece upside down and using a needle nosed tip) as to assure that a sufficient supply of said lubricant to enable the formation of an effective eutectic film during the subsequent autoclave cycle reaches, but does not go beyond, the rotor assembly during each application prior to sterilization.
7 Vastly extended effectiveness of the lubricant in the protection of the dental handpiece as a result of the sterilization process.